Variable pressure instantaneous switching unit



July 18, 1967 c. D. HARKLAU ETAL 3,331,330

VARIABLE PRESSURE INSTANTANEOUS SWITCHING UNIT Filed July 21, 1966 a m M m NM? M Qmw *QN M W" l 3 m4 me M I i Z a? M 0 United States Patent Iowa Filed July 21, 1966, Ser. No. 566,900 14 Claims. (Cl. 103-51) This invention relates to a .swtiching unit and in particular to a variable pressure instantaneous switching unit.

This application is a continuation-in-part of applicants co-pending application on a Switching Valve, Ser. No. 415,405, filed Dec. 2, 1964 which is a continuation-in-part of applicants application on a Switching Valve, Ser. No. 347,906, filed Feb. 27, 1964, now Patent No. 3,276,381.

It is one of the principal objects of this invention to provide a spring actuated spring assembly which will cause instantaneous operation of an actuation unit regardless of the amount of force applied to the spring assembly.

It is therefore another object of this invention to provide a pump having a switching valve and a spring assembly for instantaneously operating the switching valve regardless of the operating pressures and thereby providing continuous pressure output from the pump.

Yet another object of this invention is to provide a pump having a switching valve and a spring actuating assembly which includes two sets of spring means arranged in series wherein one of the spring means is relatively stronger than the other spring means; both spring means being compressed under high operating pressures while only the weaker spring is compressed under relatively lower operating pressures to thereby provide the instantaneous switching regardless of the operating pressure level.

A further object of this invention is to provide a pump having a pair of spaced apart pistons in a cylinder having a leak hole position between the pistons such that mixing of the material being acted upon by each of the piston is impossible should the material escape past the respective piston seals into the area between the two pistons.

It is yet another object of this invention to provide a switching valve which is capable of producing very high pump pressures.

It is another object of this invention to provide a switching valve which may be used as a pump for pumping cleaning materials or the like.

Yet another object of this invention is to provide a switching valve that is self-starting and will not stop on dead center.

Yet another object of this invention is to provide a switching valve which functions as a pump as the piston moves in both directions of its cycle of operation.

A further related object of this invention is to provide a switching valve having a valve assembly which is automatically actuated at the end of each half cycle of travel of the piston operatively connected thereto.

A still further object of this invention is to provide a switching valve which will function on either very low pressures on the fluid actuator piston or at very high pressures as desired.

A further object of this invention is to provide a variable pressure instantaneous switching unit wihch is simple in design, economical to manufacture and refined in appearance.

These and other objects will be apparent to those skilled in the art.

This invention consists in the construction, arrangements, and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. 1 is a fragmentary cross-sectional view of one embodiment of the switching valve unit and the piston actuating unit;

FIG. 2 is a longitudinal cross-sectional view of the switching valve employing another switching valve unit and actuating unit;

FIG. 3 is a fragmentary cross-sectional view taken along line 33 in FIG. 2;

FIG. 4 is a fragmentary cross-sectional view taken along line 44 in FIG. 2;

FIG. 5 is a schematic view of the switching valve in a pumping system; and

FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 1.

The switching valve of this invention is referred to generally in FIG. 2 by the reference numeral 10 and includes a pair of cylindrical housing sleeve 12 connected at one end to a valve body 14 and closed at their outer ends by end plates 16. The end plates 16 are clamped together by four rods 18 extending the length of the switching valve 10 and being received in notches 20 in the periphery of the valve body 14.

Inside the switching valve 10, an elongated shaft 22 extends through the valve body 14 and is provided with a pair of spaced apart pistons 24 and 26 at each of its outer ends. A sleeve element 28 maintains the pistons 24 and 26 in their spaced apart relationship and a nut 30 is used to hold the outer pistons 24 on the shaft 22.

A pair of fluid chambers 32 and 34 are defined by the pistons 26 and the valve body 14. Also, the end plates 16 and the outer pistons 24 define a pair of material chambers 36 and 38. Between the pistons 24 and 26 is a separating chamber 39 at the left end of the switching valve 10 and a separating chamber 40 at the right end thereof.

The valve body 14 is provided with a first pair of bushing elements 42 and 44 threadably engaging a valve body and having a passageway 46 extending therethrough in communication with the fluid chambers 32 and 34. An inlet fluid opening 48 is provided in communication with the passageway 46.

A second pair of bushing elements 50 and 52 are disposed diametrically opopsite the first pair of bushing elements 42 and 44. The bushing elements 50 and 52 are provided with a passageway 54 which is also in communication with the fluid chambers 32 and 34. An outlet opening 56 is formed in the valve body 14 and is in communication with the passageway 54 intermediate its ends.

In the passageway 46, a valve element 58 is slidably mounted and is provided with an enlarged portion 60 intermediate its ends having tapered sidewalls for mating sealing engagement with the inner ends of the bushings 42 and 44. As the valve element 58 moves back and forth, the enlarged portion 60 moves in a cavity 62 between the inner ends of the bushings 42 and 44. Within the bushings 42 and 44 the valve element 58 is provided with three symmetrical elongated arcuate grooves 64 as seen in FIG. 3. This provides a space for fluid to pass from the cavity 62 to either of the fluid chambers 32 and 34.

At the outer ends of the valve element 58, extension elements 66 are threadably secured and carry a coil spring 68 which extends outwardly thereof toward the fluid piston 26.

In the passageway 54, a valve element 70 extends the length thereof and is provided with enlarged end portions 72 for mating and sealing engagement with the outer ends of the bushings 50 and 52. The enlarged ends have tapered inner surfaces which correspond to the tapered countersunk outer ends of the bushings 50 and 52.

The enlarged portions 72 are spaced apart a distance greater than the length of the passageway 54 whereby only one of the enlarged portions is in seating engagement with the adjacent bushing at any given moment. Also, extension members 74 are provided on the outer ends of the enlarged portions 72 and carry thereon springs 68 as the extension members 66 on the valve element 58. The valve element 70 is also provided with a plurality of elongated arcuate grooves 76 for movement of fluid in the passageway 54.

In the end walls 16 of the switching valve are provided inlet and outlet ball valves 78 and 80 respectively.

In communication at all times with the separating chambers 39 and 40 are exhaust openings 82 and 84 respectively on the lower side of the housing members 12 such that any material from the chambers 36 and 38 which leaks past the material pistons 24 will escape by gravity through the exhaust ports 82 and 84 and similarly any valve fluid in the chambers 32 and 34 which escapes past the fluid pistons 26 will be visually indicated as it drips from the exhaust ports 82 and 84. Obviously, the pistons 24 and 26 never move across the exhaust ports 82 or 84 such that the exhaust ports are ever in communication with the fluid chambers 32 and 34 or the material chambers 36 and 38. By this arrangement it is virtually impossible for the hydraulic fluid to be mixed with the work product material upon one of the seals on the pistons 24 or 26 failing. It is to be appreciated that if the hydraulic fluid and the work product were to be mixed the valve unit would be irreparably damaged by the work product material. Without the leak holes 82 and 84 hydraulic fluid or work product material would fill up the chambers 36 and 38 and ultimately be drawn past the adjacent piston into the adjacent chamber. This cannot happen when the pressure between the pistons 24 and 26 in the chamber 39 is constantly at atmospheric pressure. Thus, the primary importance of the leak holes 82 and 84 is not to provide visual indication of seal failure but rather to absolutely prevent intermixing of the hydraulic fluid and the work product.

In FIG. 2 it is seen that a spring assembly 86 having a body member 88 is mounted on the shaft 22 on opposite sides of the valve body 14 adjacent the hydraulic fluid pistons 26. The body member 88 is slidably mounted on the shaft 22 and includes a pair of cavities 90 facing the valve body 14 for receiving the extension portions 74 and their coil springs 68. The bottom of the cavities 90 is formed by a wall 94 which is relatively thin in the area of the cavities 90 since the cavities extend substantially the full width of the body member 88.

Facing the hydraulic piston 26, are four cavities 96 in which coil springs 98 are mounted. These springs also extend substantially the full width of the spring assembly body member 88. The outer ends of the springs are adapted to bear against a washer element 100 mounted on the face of the piston 26. To prevent pressure build-up between the spring assembly holder member 88 and the pistons 26, a passageway 102 is provided connecting with the cavities 90 and a circular groove 104. The springs 68 are designed to be yieldably depressed when the pump is operating at low pressure such as 20 pounds per square inch while the four springs 98 require higher pressures such as 1200 pounds per square inch to be depressed. As shown in FIG. 2, the fluid piston head 26 has completely depressed both sets of springs such that the extension members 74 have bottomed out against the spring holder wall 94 which in turn has moved into direct engagement with the washer 100 on the fluid piston 26. This indicates that the pump has been operating under high pressures in the neighborhood of 1200 pounds per square inch. Thus it is seen, that first the fluid piston 26 engages the springs 98 and in turn moves the spring holder body member 88 against the springs 68 until they are depressed and the extension portions 74 engage the bottom wall 94 of the spring holder 88. At low pressures, this will be suflicient to instantaneously actuate the valve elements to give fast switching thereby maintaining a constant material output volume and pressure. When operating at high pressures, the two sets of springs 68 and 98 will bottom out such that essentially direct engagement is provided between the piston 26 and the valve elements and at this instant of engagement, the compressed springs will instantaneously actuate the valve elements. Thus it is seen that by the use of the spring assembly 86 the pump may be operated at any pressure because of the instantaneous switching of the valve elements which will provide continuous output pressure from the material chambers 36 and 38.

In FIG. 5 the switching valve 10 is illustrated in a pumping system and is shown provided with a reservoir of hydraulic fluid or the like 110 which is transmitted by a pump 112 to the inlet opening 48. A return conduit 114 is connected to the outlet opening 56. A release valve 116 is disposed between the pump 112 and the return conduit 114 to prevent subjecting the switching valve 10 to too great a pressure.

Cleaning fluid or the like from the material supply (not shown) is drawn in through the valves 78 and pumped out from the chambers 36 and 38 through the valves into a common outlet discharge conduit 118.

In operation it is seen from FIG. 2 that the shaft 22 with its pistons 24 and 26 has moved to the extreme right position and by the left hand fluid piston 26 hearing against the spring holder assembly 86 the valve elements 58 and 70 have been moved to their extreme right hand positions. At this point then, fluid entering the opening 48 will pass into the cavity 62 and along the valve element in the groove 64 and into the fluid chamber 32. The pressure building up in the chamber 32 will force the piston 26 t0 the left and accordingly the piston 24 to the left thereby discharging material from the chamber 36 out through the outlet valve 80. At the same time the right hand fluid piston 26 is forcing fluid from the fluid chamber 34 into the passageway 54 along the valve element 70 and up through the outlet opening 56 where it is returned by way of the return conduit 114 to the reservoir 110. It is also seen that any air in the system will rise and flow with the fluid out of the top outlet opening 56. As soon as the pistons move to their extreme left hand position, the right hand fluid piston 26 will engage the spring 68 in the fluid chamber 34 and when suflicient pressure is exerted on the valve elements 58 and 70 they will both simultaneously and instantaneously move to the extreme left at which time the fluid entering the inlet opening 48 will be directed past the enlarged portion 60 in the cavity 62 and to the chamber 34 and the fluid from the chamber 32 will exit through the passageway 54 out the outlet opening 56. This cycle will be repeated over and over again and can be performed at varying pressures within the chambers 32 and 34. Very low pressures will cause the switching valves 10 to operate since the valve elements 58 and 70 have only a short distance to move to reverse the direction of the pistons 24 and 26 and the release of energy in the springs 68 and 98 causes the instantaneous switching of the valve elements. The shaft 22 and the pistons 24 and 26 are free floating and in operation continually rotate thereby distributing any wear in the system over a large area. For example, the springs 98 contact the washer at different points in each cycle of operation. Consequently, the wear is evenly distributed around the inner face of the washers 100.

It is apparent that it is almost impossible for the valve mechanism to stop on dead center. For this to occur each of the valve elements 70 and 58 and the pistons 26 would have to be on dead center. Also, fluid enters the inlet opening 48 and it will normally flow to one side or the other of the shoulder 60. Thus the valve mechanism is self-starting regardless of the relative positions of the components before the machine is started.

In further reference to FIG. 2, it is seen that the pistons 26 are mounted on the shaft 22 by a pair of semi cylindrical sleeve inserts 120 mounted in an annular recess 122 formed in the shaft 22. The ends of the annular recess 122 hold the semi cylindrical inserts 120 against longitudinal movement. An annular flange 124 on the elements 120 serves to engage and hold the washer at 100 in position against the inner face of the piston 26.

In FIGS. 1 and 6, it is seen that a modified embodiment is illustrated wherein the piston 26A is provided with a plurality of spring cavities 200. The weaker springs 202 are disposed in cavities diametrically opposite each other and these springs are longer than the adjacent pair of stronger springs 204 which are also disposed diametrically opposite each other to provide uniform pressures on the piston 26A. The sleeve inserts 120 serve to lock the piston 26A on the shaft 22 against the spacer sleeve 28 A force transfer plate 206 is movably mounted on the piston shaft 22 between asnap lock ring 208 and the springs 202 and 204.

The valve elements 56A. and 70A are provided with enlarged cylindrical heads 209 for engagement with the force transfer plate 206. It is seen that the space requirements for the structure are substantially reduced since the valve elements 56A and 70A are substantially shorter and the springs are mounted in the piston rather than in a separate spring holder. A relatively thin force transfer plate 206 is sufficient to transfer the spring pressures to the valve elements as the pistons reciprocate. In further reference to the force transfer plate 206, it is seen that a wear resistant and strengthening annular shoulder 210 is provided for engagement with the lock snap ring 208. Also, an annular recess 212 is provided on the opposite face of the force transfer plate 206 to matingly receive the flanges of the sleeve inserts 120 such that when the springs are all compressed the adjacent surfaces of the force transfer plate 206 and the piston 26A will meet in mating engagement.

Thus in operation it is readily seen that as the piston 26A moves to the left as viewed in FIG. 1, the longer but weaker springs 202 will first engage the force transfer plate 206 and as the piston and shaft move further to the left the force transfer plate will engage the valve element head portions 209 and thereby move them to their left-hand positions. Again, depending on the pressure within the switching valve system, the valve elements 56A and 70A may be switched by operation of the longer but weaker springs 202 but if the pressure requirements are higher then the springs 202 will be compressed and thus bring the shorter but stronger springs 204 into engagement with the force transfer plate 206. Either way, the

' end result is that the valve elements 56A and 70A will be simultaneously switched regardless of the pressures Within the valve system. Thus it is readily seen that this switching valve system will give continuous smooth operation and thereby eliminate the pressure-drop commonly occurring in conventional pump systems. The use of the strong and Weak springs makes the switching occur literally instantaneously.

Some changes may be made in the construction and arrangement of our variable pressure instantaneous switching unit without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

We claim:

1. A switching valve assembly, comprising,

a housing,

an actuation unit in said housing,

a reciprocating means in said housing,

a spring assembly in said housing between said actuation unit and said reciprocating means,

actuating means for alternately moving said reciprocating means into and out of actuating engagement with said spring assembly, said actuation unit including element means connected to said actuating means and positioned to be engaged and actuated by said spring assembly when said reciprocating means moves a predetermined distance towards said spring assembly,

said spring assembly including first and second spring means, said first spring means being stronger than said second spring means, said first and second spring means being positioned in series to store and transfer force from said reciprocating means through said element means to said actuating means.

2. The structure claim 1 wherein said spring assembly includes a body member and said first and second spring means of said spring assembly are positioned on opposite sides of said body member for one of said first and second spring means to engage said reciprocating means and the other of said first and second spring means to engage said element means.

3. The structure of claim 2 wherein said body member positioned between said first and second spring means is so arranged that upon said second spring means being compressed a predetermined amount said body member bottoms out against the adjacent element means or reciprocating means.

4. The structure of claim 3 wherein said first spring means is so positioned that upon being compressed a predetermined amount said body member bottoms out against the adjacent element means or reciprocating means.

5. The structure of claim 4 and said reciprocating means is mounted on a shaft slidably received in said actuating unit and said spring assembly including said body member is slidably mounted on said shaft.

6. The structure of claim 5 wherein said one of said first and second spring means is mounted in a cavity formed in said body member and the other of said first and second means is telescopically mounted on said element means, said body member having a cavity to receive said other spring means on said elements, and said cavities extending from opposite sides of said body member substantially the entire length of said body member.

7. The structure of claim 6 wherein said shaft extends through said actuation unit and a second reciprocating means is connected to said shaft, a second spring assembly is slidably mounted on said shaft between said actuation unit and said second reciprocating means, a second element means is connected to said actuating means and positioned to be engaged by and actuated by said second spring assembly when said second reciprocating means moves a predetermined distance towards said second spring assembly, said second spring assembly including first and second spring means, said first spring means being stronger than said second spring means, said first and second spring means being positioned in series to transfer force from said second reciprocating means through said second element means to said actuating means, said first and second spring means of said second spring assembly being positioned on opposite sides thereof for one of said first and second spring means to engage said second reciprocating means and the other of said first and second spring means to engage said second element means, said second spring assembly including a body member positioned between said first and second spring means and being so arranged that upon said second spring means being compressed a predetermined amount said body member bottoms out against the adjacent second element means or second reciprocating means, said first spring means being so positioned that upon being compressed a predetermined amount said body member bottoms out against the adjacent second element means or second reciprocating means.

8. The structure of claim 7 wherein said second spring assembly one of said first and second spring means is mounted in a cavity formed in said body member and the other of said first and second spring means is telescopical- 1y mounted on said second element means, said body member having a cavity to receive said other spring means on said second element means, and said cavity extending from opposite sides of said body member substantially the entire length of said body member.

9. The structure of claim 5 wherein said shaft extends through said actuation unit and a second reciprocating means is connected to said shaft, a second spring assembly is slidably mounted on said shaft between said actuation unit and said second reciprocating means, a second element means is connected to said actuating means and positioned to be engaged by and actuated by said second spring assembly when said second reciprocating means moves a predetermined distance towards said second spring assembly, said second spring assembly including first and second spring means, said first spring means being stronger than said second spring means, said first and second spring means being positioned in series to transfer force from said second reciprocating means through said second element means to said actuating means, said first and second spring means of said second spring assembly being positioned on opposite sides thereof for one of said first and second spring means to engage said second reciprocating means and the other of said first and second spring means to engage said second element means, said second spring assembly including a body member positioned between said first and second spring means and being so arranged that upon said second spring means being compressed a predetermined amount said body member bottoms out against the adjacent second element means or second reciprocating means, said first spring means being so positioned that upon being compressed a predetermined amount said body member bottoms out against the adjacent second element means or second reciprocating means.

10. In a switching valve, comprising,

a housing, said housing having an end wall at opposite ends thereof,

a valve body disposed in said housing,

a chamber in said housing on each side of said valve body,

a shaft slidably extending through said valve with end portions disposed in each of said chambers,

a piston assembly on each end portion in each chamber,

each piston and the adjacent side of said valve body defining a pair of fluid chambers,

each of said end walls and the adjacent piston assembly defining a pair of material chambers,

a material inlet and a material outlet in communication with each of said material chambers,

a fluid inlet and a fluid outlet,

valve means for alternately at times in one position placing said fluid inlet in communication with one of said fluid chambers and said fluid outlet in communication with said other fluid chamber and at other times in a second position placing said fluid inlet in communication with said other fluid chamber and said fluid outlet in communication with said one fluid chamber, and

actuating means on said shaft for moving said valve means back and forth between said first and second positions as said shaft moves a predetermined distance in one direction and then a predetermined distance in the opposite direction,

said actuating means including a spring assembly on each shaft end portion between said piston assembly and said valve body, said spring assembly having a body member and first and second spring means arranged on opposite sides thereof, one of said first and said second spring means being relatively stronger than the other of said first and second spring means, said valve means having a portion exposed on each side of said valve body for engagement by said first spring means and said second spring means posi tioned to be compressed between said adjacent piston and said body member upon said piston moving said predetermined distance.

11. The structure of claim 10 wherein said first spring means arranged for said exposed portion of said valve means to engage said spring assembly body member upon said first spring being compressed a predetermined amount and said piston to engage said spring assembly body member upon said second spring means being compressed a predetermined amount.

12. The structure of claim 11 wherein each of said spring assembly bodies have cavities on opposite sides thereof in which said first and said second spring means are positioned and said cavities have a depth extending substantially the axial length of said spring assembly body.

13. In a switching valve, comprising,

a housing, said housing having an end wall at opposite ends thereof,

a valve body disposed in said housing,

a rghaimber in said housing on each side of said valve a shaft slidably extending through said valve with end portions disposed in each of said chambers,

a piston assembly on each end portion in each chameach piston and the adjacent side by said valve 'body defining a pair of fluid chambers,

each of said end walls and the adjacent piston assembly defining a pair of material chambers,

a material inlet and a material outlet in communication with each of said material chambers,

a fluid inlet and a fluid outlet,

valve means for alternately at times in one position placing said fluid inlet in communication with one of said fluid chambers and said fluid outlet in communication with said other fluid chamber and at other times in a second position placing said fluid inlet in communication with said other fluid chambet and said fluid outlet in communication with said one fluid chamber, and

actuating means on said shaft for moving said valve means back and forth between said first and second positions as said shaft moves a predetermined distance in one direction and then a predetermined distance in the opposite direction,

said actuating means including a movable force transfer plate on each shaft end portion between said piston assembly and said valve body, first and second spring means positioned in said piston and extending towards said plate, said first spring means extending further out of said piston and being weaker relative to said second spring means, said valve means having a portion exposed on each side of said valve body for engagement by said force transfer plate upon the adjacent piston moving at least said first spring means into engagement with said plate.

14. In a switching valve, comprising,

a housing, said housing having an end wall at opposite ends thereof,

a valve body disposed in said housing,

a cjhalmber in said housing on each side of said valve a shaft slidably extending through said valve with end portions disposed in each of said chambers,

a piston assembly on each end portion in each chameach piston and the adjacent side of said valve body defining a pair of fluid chambers,

each of said end walls and the adjacent piston assembly defining a pair of material chambers,

a material inlet and a material outlet in communication with each of said material chambers,

a fluid inlet and a fluid outlet,

valve means for alternately at times in one position placing said fluid inlet in communication with one of said fluid chambers and said fluid outlet in comactuating means on said shaft for moving said valve means back and forth between said first and second positions as said shaft moves a predetermined distance in one direction and then a predetermined of said first and second spring means, said valve means having a portion exposed on each side of said valve body for engagement by said spring assembly, said first and second spring means being positioned for the Weaker spring and then the stronger spring to be compressed upon said piston moving said predetermined distance.

References Cited distance in the opposite direction,

said actuating means including a spring assembly on 10 UNITED STATES PATENTS each shaft end portion between said piston and said 2,925,783 2/1960 fp 6t 10352 valve body, said spring assembly having first and 3,256,827 6/1966 Smlth 103-51 second spring means, one of said first and second spring means being relatively stronger than the other 15 ROBERT WALKER, y Examine!- 

1. A SWITCHING VALVE ASSEMBLY, COMPRISING, A HOUSING, AN ACTUATION UNIT IN SAID HOUSING, A RECIPROCATING MEANS IN SAID HOUSING, A SPRING ASSEMBLY IN SAID HOUSING BETWEEN SAID ACTUATION UNIT AND SAID RECIPROCATING MEANS, ACTUATING MEANS FOR ALTERNATELY MOVING SAID RECIPROCATING MEANS INTO AND OUT OF ACTUATING ENGAGEMENT WITH SAID SPRING ASSEMBLY, SAID ACTUATION UNIT INCLUDING ELEMENT MEANS CONNECTED TO SAID ACTUATING MEANS AND POSITIONED TO BE ENGAGED AND ACTUATED BY SAID SPRING ASSMBLY WHEN SAID RECIPROCATING MEANS MOVES A PREDETERMINED DISTANCE TOWARDS SAID SPRING ASSEMBLY, SAID SPRING ASSEMBLY INCLUDING FIRST AND SECOND SPRING MEANS, SAID FIRST SPRING MEANS BEING STRONGER THAN SAID SECOND SPRING MEANS, SAID FIRST AND SECOND SPRING MEANS BEING POSITIONED IN SERIES TO STORE AND TRANSFER FORCE FROM SAID RECIPROCATING MEANS THROUGH SAID ELEMENT MEANS TO SAID ACTUATING MEANS. 